SISTEMA DIGESTIVO

1. SISTEMA DIGESTIVO

3. SISTEMA DIGESTIVO: bioreactores

4. SISTEMA DIGESTIVO Es un tubo abierto: extensión del medio ambiente! S E absorción • Digestión: • mecánica (trituración) • química (enzimas hidrolíticas)

5. Sistema de Tubos y Esfínteres • Direccionalidad • Compartimentalización • Almacenamiento.

6. EL TRACTO DIGESTIVO

7. Anatomía del sistema digestivo • Digestive tract • Alimentary tract or canal • GI tract • Accessory organs • Primarily glands • Regions • Mouth or oral cavity • Pharynx • Esophagus • Stomach • Small intestine • Large intestine • Anus

8. Cavidad oral • Mouth or oral cavity • Vestibule: Space between lips or cheeks and alveolar processes • Oral cavity proper • Lips (labia) and cheeks • Palate: Oral cavity roof • Hard and soft • Palatine tonsils • Tongue: Involved in speech, taste, mastication, swallowing

9. Dientes

10. Dientes • Two sets • Primary, deciduous, milk: Childhood • Permanent or secondary: Adult (32) • Types • Incisors, canine, premolar and molars

11. Glándulassalivales • Produce saliva • Prevents bacterial infection • Lubrication • Contains salivary amylase • Breaks down starch • Three pairs • Parotid: Largest • Submandibular • Sublingual: Smallest

13. Producción de saliva • - 99.5 % agua • HCO3- , ph 6.5 • moco, enzimas

14. SECRECIONES SALIVALES1. Secreción serosa: amilasasalival: • hidrólisisa-1-4 polisacáridos • Secreción mucosa: • lubrica y protege. • IgA y lisozima: • antimicrobiana

15. Reflejo de deglución • Fase voluntaria • Bolo alimenticio desde boca a faringe • Fase refleja • Apertura del esófago, • cierre de laringe • Fase refleja • Transporte por esófago

16. Histología del tracto digestivo

17. Peritoneo y Mesenterios • Peritoneum • Visceral: Covers organs • Parietal: Covers interior surface of body wall • Retroperitoneal: Behind peritoneum as kidneys, pancreas, duodenum • Mesenteries • Routes which vessels and nerves pass from body wall to organs • Greater omentum • Lesser omentum

18. Estómago • Openings • Gastroesophageal: To esophagus • Pyloric: To duodenum • Regions • Cardiac • Fundus • Body • Pyloric

19. Histología del estómago • Layers • Serosa or visceral peritoneum: Outermost • Muscularis: Three layers • Outer longitudinal • Middle circular • Inner oblique • Submucosa • Mucosa

22. Gastric pits and glands: • Contain cells • Surface mucous: Mucus • Mucous neck: Mucus • Parietal: Hydrochloric acid and intrinsic factor • Chief: Pepsinogen • Endocrine: Regulatory hormones

23. Secreción de HClen célulasparietales

24. Barrera mucus – HCO3-

25. Fases de la secrecióngástrica

26. FASE CEFÁLICA - percepción sensorial del alimento

27. FASE GÁSTRICA - presencia del alimento

28. Ondas de mezcla

29. FASE INTESTINAL VIP Gastrin

31. Duodeno y Pancreas

32. Anatomy Endocrine Pancreatic islets produce insulin and glucagon Exocrine Acini produce digestive enzymes and HCO3- Regions: Head, body, tail Secretions Pancreatic juice (exocrine) Trypsin Chymotrypsin Carboxypeptidase Pancreatic amylase Pancreatic lipases Elastase Nucleases (DNA, RNA) HCO3-, H20 Pancreas

35. Secreción de HCO3-

36. Enzimas • Trypsinogen • Chymotrysinogen • Carboxypeptidases • Pro-elastase • Phospholipase • pancreatic lipase • Pancreatic amylase

37. Hígado • Lobes • Major: Left and right • Minor: Caudate and quadrate • Ducts • Common hepatic • Cystic • From gallbladder • Common bile • Joins pancreatic duct at hepatopancreatic ampulla

39. Histología del hígado triada portal Figure 24.20a, b

40. Funciones del hígado • Bile production • Salts emulsify fats, contain pigments as bilirubin • Storage • Glycogen, fat, vitamins, copper and iron • Aminoacid synthesis • Cholesterol and tryglicerid synthesis • Gluconeogénesis, glucogénesis, glucogenólisis • Hepatocytes remove ammonia and convert to urea • Phagocytosis • Kupffer cells phagocytize worn-out and dying red and white blood cells, some bacteria • Plasma proteins and hemostatic factors • Albumins, globulins, fibrinogen, heparin, K vitamin • Detoxification and drug metabolism • Hormonal secretion: trombopoietin, angotensinogen

41. Bilis …each day around 600 ml of bile is produced… • Bile acid • Phospholipids • Cholesterol • Bilirubin • Waste products • Electrolytes • Mucin • HCO3-

42. Conductos

43. Intestinodelgado • Site of greatest amount of digestion and absorption • Divisions • Duodenum • Jejunum • Ileum: Peyer’s patches or lymph nodules • Modifications • Circular folds or plicae circulares, villi, lacteal, microvilli • Cells of mucosa • Absorptive, goblet, granular, endocrine

44. Secreciones del int. delgado • Mucus and HCO3- • Protects against digestive enzymes and stomach acids • Enzymes • Disaccharidases • Peptidases • Nucleotidases, nucleosidases • Enteroquinase: tripsinógeno tripsina • Duodenal glands (Brünner) • Stimulated by vagus nerve, secretin, chemical or tactile irritation of duodenal mucosa

45. Duodenollegan: quimoácido, jugospancreáticos, bilis

46. Absorción intestinal

47. Monosacáridos

48. Lípidos

49. Lipoproteinas • Types • Chylomicrons • Enter lymph • VLDL • LDL • Transports cholesterol to cells • HDL • Transports cholesterol from cells to liver

50. Intestinogrueso • Extends from ileocecal junction to anus • Consists of cecum, colon, rectum, anal canal • Movements sluggish (18-24 hours)